نتایج جستجو برای: cattle breeding
تعداد نتایج: 104336 فیلتر نتایج به سال:
Breeding objectives for beef cattle in Ireland were derived and used to define selection sub-indexes. The intention of the sub-indexes was to simplify selection decisions by commercial bull and semen buyers for situations where all of the resulting progeny are slaughtered, or when some female progeny are kept as replacement breeding cows. Separate sets of economic values for calving ease and ge...
The objective of this thesis was to evaluate genetic aspects of longevity (LPL) in the Chianina beef cattle population in order to define how to include this trait in selection criteria. The Chianina breed has been raised for over twenty-two centuries in Italy and today this breed is present in different countries across Europe, South and Central America, Australia, Canada and the USA. Its char...
The Brown-headed Cowbird (Molothrus ater) is a widespread brood parasite which often engages in a commensalistic feeding relationship with domestic livestock. We studied the behavior of female cowbirds breeding in pinyon–juniper woodlands in New Mexico, USA, on two adjacent sites, one an active cattle ranch, and the other a site that was not grazed by domestic livestock throughout the songbird ...
We investigatehow variation in breeding plumes in uences pairing patterns, extra-pair copulations and breeding performance in the colonial cattle egret (Bubulcus ibis ibis). The breeding plumes of both male and female cattle egrets varied from almost none, to lush head, back and scapular plumes. Overall, male breeding plumes were longer and darker than those of females, but we observed the ful...
The objective of the present study was to determine the grades of nonspecific bacterial infection of genitalia of repeat breeding cattle by a simple and rapid test under field condition. For this purpose, a total of 100 crossbred Jersey cows comprising of 80 repeat breeding animals presented for treatment and 20 normal cyclic (control group) animals presented for artificial insemination at thei...
Genomic selection has been widely used for complex quantitative trait in farm animals. Estimations of breeding values for slaughter traits are most important to beef cattle industry, and it is worthwhile to investigate prediction accuracies of genomic selection for these traits. In this study, we assessed genomic predictive abilities for average daily gain weight (ADG), live weight (LW), carcas...
Antibodies against bovine leukaemia virus were detected in 322 of 1,511 serum samples from cattle of various age groups and both sexes, in various herds of the country. A variable degree (5.4 to 75%) of positive reactors was recorded in individual herds where no systematic breeding policy had been followed. Antibodies were also detected in clinically healthy cattle, having normal haematological...
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